What happens to memory allocated using new if we lose the pointer to it?

The new operator creates the object using that memory, and then returns a pointer containing the address of the memory that has been allocated. Without a pointer to hold the address of the memory that was just allocated, we’d have no way to access the memory that was just allocated for us!

Can we resize the allocated memory which was allocated using new operator?

The C++ FAQ states that memory allocated by new cannot be resized by realloc, so what’s the correct way to regrow memory allocated by new? There isn’t an analogous operation to realloc with the C++ new / delete system (by default). If you need to use new , you probably really want an std::vector .

What will happen if a memory allocated at the heap is not deleted?

Or? If you don’t free/delete dynamically allocated arrays they don’t get freed/deleted. That’s all. Use vector it deletes itself automatically and has a push_back function to add new elements to the existing array.

What happens to the memory reserved for a function when the function finishes executing?

When the function finally exits, its local storage is deallocated. Locals 101: When a function is called, memory is allocated for all of its locals. Finally, when the function finishes and exits, its locals are deallocated.

Where the memory is added if the new size of the memory block is larger than the old size?

If the new size is larger than the old size, the added memory is not initialized. Explanation: The free() function frees the memory state pointed by a pointer and returns no value.

Does the heap memory get de allocated after program execution?

In a stack, the allocation and de-allocation are automatically done by the compiler whereas in heap, it needs to be done by the programmer manually.

What is realloc () in C?

In the C Programming Language, the realloc function is used to resize a block of memory that was previously allocated. The realloc function allocates a block of memory (which be can make it larger or smaller in size than the original) and copies the contents of the old block to the new block of memory, if necessary.